This name derives from the Irish clan surname originally “MacClancy”, meaning “the son of the red warrior or Reddish, ruddy”, from the Irish (Gaelic) Mac Fhlannchaidh. 1) Mac Fhlannchaidh of Breifne were chiefs of Dartraighe, in what is now County Leitrim. 2) The Mac Fhlannchaidh of Thomond were a branch of the Mac Conmara family, acted as hereditary lawyers to the O'Briens. Their homeland was in the barony of Corcomroe in north County Clare. In addition Clancy, in English language, means “overflow or spillage”.